/*
 * Copyright 2002-2018 the original author or authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.springframework.http.codec.support;

import java.util.Collections;
import java.util.List;

import org.springframework.core.codec.Encoder;
import org.springframework.http.codec.FormHttpMessageReader;
import org.springframework.http.codec.HttpMessageReader;
import org.springframework.http.codec.HttpMessageWriter;
import org.springframework.http.codec.ServerCodecConfigurer;
import org.springframework.http.codec.ServerSentEventHttpMessageWriter;
import org.springframework.http.codec.multipart.MultipartHttpMessageReader;
import org.springframework.http.codec.multipart.SynchronossPartHttpMessageReader;
import org.springframework.lang.Nullable;
import org.springframework.util.ClassUtils;

/**
 * Default implementation of {@link ServerCodecConfigurer}.
 *
 * @author Rossen Stoyanchev
 * @since 5.0
 */
public class DefaultServerCodecConfigurer extends AbstractCodecConfigurer implements ServerCodecConfigurer {

    static final boolean synchronossMultipartPresent =
            ClassUtils.isPresent("org.synchronoss.cloud.nio.multipart.NioMultipartParser",
                    DefaultServerCodecConfigurer.class.getClassLoader());


    public DefaultServerCodecConfigurer() {
        super(new ServerDefaultCodecsImpl());
    }

    @Override
    public ServerDefaultCodecs defaultCodecs() {
        return (ServerDefaultCodecs) super.defaultCodecs();
    }


    /**
     * Default implementation of {@link ServerDefaultCodecs}.
     */
    private static class ServerDefaultCodecsImpl extends AbstractDefaultCodecs implements ServerDefaultCodecs {

        @Nullable
        private Encoder<?> sseEncoder;

        @Override
        public void serverSentEventEncoder(Encoder<?> encoder) {
            this.sseEncoder = encoder;
        }

        @Override
        List<HttpMessageReader<?>> getTypedReaders() {
            if (!shouldRegisterDefaults()) {
                return Collections.emptyList();
            }
            List<HttpMessageReader<?>> result = super.getTypedReaders();
            result.add(new FormHttpMessageReader());
            if (synchronossMultipartPresent) {
                SynchronossPartHttpMessageReader partReader = new SynchronossPartHttpMessageReader();
                result.add(partReader);
                result.add(new MultipartHttpMessageReader(partReader));
            }
            return result;
        }

        @Override
        List<HttpMessageWriter<?>> getObjectWriters() {
            if (!shouldRegisterDefaults()) {
                return Collections.emptyList();
            }
            List<HttpMessageWriter<?>> result = super.getObjectWriters();
            result.add(new ServerSentEventHttpMessageWriter(getSseEncoder()));
            return result;
        }

        @Nullable
        private Encoder<?> getSseEncoder() {
            if (this.sseEncoder != null) {
                return this.sseEncoder;
            }
            return jackson2Present ? getJackson2JsonEncoder() : null;
        }
    }

}
